1. Field of the Invention
The present invention relates to an operation system, for transmission devices on a network, which manages information inherent to the operation system, and control and monitoring information for the transmission devices, by using a database of MIB (Management Information Base) management process, and to an alarm monitoring method therefor. The MIB is a set of management objects which are units of management information for a network management function.
2. Related Arts
Recently, for the operation system, in addition to the implementation of control and monitoring for a plurality of transmission devices, a need has been noted for a real-time process and operational reliability for the control and monitoring of the transmission devices on the network.
FIG. 8 is a schematic diagram illustrating a network. In FIG. 8, a station terminal 200a for a subscriber A and a station terminal 200b for a subscriber B are connected together by a relay transmission path 300. A plurality of network centers 400, which serve as relay terminals, are provided along the relay transmission path 300.
Each of the station terminals 200a and 200b includes a switch 202; a terminal device 201, which serves as an interface between a subscriber line and the switch; a multiplexer 203 for multiplexing a plurality of lines; and a cross connector 204 for connecting and switching the transmission paths.
The network center 400 includes a multiplexer 401 and across connector 402. A transmission device according to the present invention comprises the above described mulitplexers 203 and 401 and the cross connectors 204 and 402.
FIG. 9 is a diagram illustrating the arrangement of a operation system for transmission device (OPS). In FIG. 9, a plurality of transmission devices 401, 402 . . . and n located in the network 400, for example, are controlled by an operation system (OPS) 100. In the operation system 100, as will be described later, alarm notifications transmitted by the transmission devices are processed by a CPU 101, operation processing means, in accordance with an alarm monitoring program stored in a memory 102. The alarm notifications transmitted by the transmission devices are entered in a database 103. The processing results obtained by the CPU 101 are displayed on a display 104, and may be printed by a printer (not shown). The operation system 100 is provided for the station terminals 200 and network centers 400.
FIG. 10 is a diagram illustrating the configuration of the alarm monitoring program. As is shown in FIG. 10, the program is composed of four layers: a GUI (Graphical User Interface) process, a MIB management process, a manager process, and a communication control process.
The GUI process is a process for interfacing with a user, and includes a control process for controlling the transmission devices and a supervision process for supervising the transmission devices.
The MIB management process uses a database to manage a set of objects, which are information units to be managed in the GUI process.
The manager process serves as an interface between the MIB management process and the transmission devices. The communication control process is a process for controlling the physical communication functions of the transmission devices. These processes are managed by an operating system (OS).
FIG. 11 is a diagram for explaining an operational concept for a conventional operation system. In FIG. 11, a MIB management process 01 includes a control reception thread 02, control threads 03 and 04, a database (DB) 05, a response reception thread 06 and a notification thread 07. A thread is a processing unit in a process which is performed.
A notification thread queue 08 is provided in the memory 102 as an area where a notification message from the response reception thread 06 is enqueued when the notification thread 07 is in the operating state (BUSY). In this specification, term `enqueue` means add an element(message) to a queue`.
Control processes 09 and 10 and a monitoring process 11 are GUI processes in FIG. 10, at a higher level than the MIB management process 01. The results obtained by the monitoring process 11 are displayed as a monitoring screen 16 on the display 104.
A manager process 12 serves as an interface for controlling and monitoring a plurality of transmission devices.
In FIGS. 12 through 16 are shown operation sequences of the conventional operation system. In FIG. 12 is represented an example where the transmission device detects a change in its state and transmits an autonomous alarm notification. In FIG. 12, the response reception thread 06 receives the autonomous alarm notification (1) from the manager process 12 and transmits it to the notification thread 07, which is in a standby state (IDLE). Upon the receipt of the autonomous alarm notification (1), the notification thread 07 is set to the operating state (BUSY) and enters the autonomous alarm notification (1) in the database DB 05. When the notification thread 07 receives a setup response (1), it transmits the autonomous alarm notification (1) to the monitoring process 11, and returns to the standby state (IDLE).
FIG. 13 represents an example where an autonomous alarm notification is transmitted by a plurality of transmission devices. The response reception thread 06 receives an autonomous alarm notification (2) from the manager process 12, and transmits it to the notification thread 07 in the standby state. Upon the receipt of the autonomous alarm notification (2), the notification thread 07 is set to the operating state (BUSY), and enters the autonomous alarm notification (2) in the database DB 05. When the notification thread 07 receives a setup response (2), it transmits the autonomous alarm notification (2) to the monitoring process 11.
At this time, the response reception thread 06 may receive the autonomous alarm notifications (3) and (4) from the manager process 12 before it transmits the autonomous alarm notification (2) to the monitoring process 11. In this case, since the notification thread 07 is in the operating state (BUSY), the autonomous alarm notifications (3) and (4) are sequentially enqueued in the notification thread queue 08.
When the notification thread 07 has transmitted the autonomous alarm notification (2), it dequeues an autonomous alarm notification (3) from the notification thread queue 08. In this specification, term `dequeue` means `take out an element (message) from a queue`. As well as for the autonomous alarm notification (2), the notification thread 07 enters the autonomous alarm notification (3) in the database DB 05, and transmits it to the monitoring process 11. The notification thread 07 performs the same process for the autonomous alarm notification (4), and returns to the standby state (IDLE).
FIG. 14 represents an example where the alarm state of the transmission device is acquired by the performance of the monitoring process 11. In this case, much time and many procedures are required to directly access the transmission device (i.e., to shift down to the communication control process in FIG. 10) in order to obtain its alarm state. Therefore, for simplification, the autonomous alarm notification is read which has been entered in the database DB 05 during the MIB management process, explained while referring to FIGS. 12 and 13.
Specifically, when the control reception thread 02 receives an alarm re-transmission request from the monitoring process 11, it transmits it to the control thread 03, which is in the standby state (IDLE). Upon the receipt of the alarm re-transmission request, the control thread 03 is set to the operating state (BUSY), reads all the autonomous alarm notifications from the database DB 05, and transmits them as alarm re-notifications to the monitoring process 11. In FIG. 14, the alarm re-notifications (1), (2), . . . and (5) correspond to the autonomous alarm notifications (1), (2), . . . and (5). Finally, the control thread 03 transmits an alarm re-transmission response to the monitor process 11, and returns to the standby state (IDLE).
FIG. 15 represents an example where an autonomous alarm notification is output during the transmission of the alarm re-notification. The control reception process 02 receives an alarm re-notification request from the monitoring process 11 and transmits it to the control thread 03, which is in the standby state (IDLE). Upon the receipt of the alarm re-notification request, the control thread 03 is set to the operating state (BUSY), reads all the autonomous notifications from the database DB 05, and transmits them as alarm re-notifications to the monitoring process 11 in the same manner as in FIG. 14. Finally, the control thread 03 transmits an alarm re-transmission response to the monitoring process 11.
As is shown in FIG. 15, before the control thread 03 transmits the alarm re-notification (5) to the monitoring process 11, the response reception thread 06 receives the autonomous alarm notification (5) from the manager process 12 and transmits it to the notification thread 07. Then, the notification thread 07 enters the autonomous alarm notification (5) in the database DB 05, and transmits it to the monitoring process 11. Following this, the alarm re-notification (5) is transmitted to the monitoring process 11. Therefore, as will be described later, the processing order for a new autonomous alarm notification and for an alarm re-notification corresponding to the preceding autonomous alarm notification is inverted.
In FIG. 16, the control reception thread 02 receives an alarm re-transmission request from the monitoring process 11, and returns a control thread BUSY error to the monitoring process 11.
Such a conventional operation system, however, has the following problems. First, in FIG. 13, when an autonomous alarm notification is frequently transmitted by the manager process 12, the process performed by the notification thread 07 can not catch up with it because of the time required to access the database DB 05, so that the autonomous alarm notification can not be transmitted to the monitoring process 11 in real time.
In addition, in FIG. 15, if, during the alarm re-transmission, the monitoring process 11 receives the autonomous alarm notification from the notification thread 07 before the process 11 receives all the alarm re-notifications from the control thread 03, the processing order for the alarm re-notification and for the autonomous alarm notification is inverted.
Specifically, the autonomous alarm notification output during the transmission of the alarm re-notification, is an alarm to provide notification of the occurrence of a new obstacle in the transmission device. When the alarm re-notification is information for providing notification of the recovery from an obstacle previously, these two notifications may be inverted and transmitted to the monitoring process 11, so that the monitoring process 11 will be notified that the new obstacle has been removed.